import asyncio
import os
import sys
from datetime import datetime
from pathlib import Path
from typing import Any

from bson import ObjectId
from pymongo import MongoClient

# Ensure "app" imports resolve when running this script directly.
BACKEND_ROOT = Path(__file__).resolve().parent.parent
if str(BACKEND_ROOT) not in sys.path:
    sys.path.insert(0, str(BACKEND_ROOT))

from app.database import close_db, connect_db, get_db


COLLECTIONS = (
    "users",
    "documents",
    "verifications",
    "refresh_tokens",
    "password_reset_tokens",
    "revoked_access_tokens",
    "notifications",
    "document_versions",
)


def _normalize(value: Any) -> Any:
    if isinstance(value, ObjectId):
        return str(value)
    if isinstance(value, datetime):
        return value
    if isinstance(value, list):
        return [_normalize(item) for item in value]
    if isinstance(value, dict):
        return {key: _normalize(item) for key, item in value.items()}
    return value


async def migrate() -> None:
    mongodb_uri = os.getenv("MONGODB_URI")
    db_name = os.getenv("MONGODB_DB_NAME") or os.getenv("DB_NAME") or "accujuris"

    if not mongodb_uri:
        raise RuntimeError("Set MONGODB_URI before running this migration script.")

    mongo_client = MongoClient(mongodb_uri)
    source_db = mongo_client[db_name]

    await connect_db()
    try:
        target_db = get_db()
        for name in COLLECTIONS:
            source_collection = source_db[name]
            target_collection = getattr(target_db, name)
            moved = 0
            for source_doc in source_collection.find({}):
                normalized = _normalize(source_doc)
                normalized["_id"] = str(source_doc["_id"])
                await target_collection.insert_one(normalized)
                moved += 1
            print(f"{name}: migrated {moved} rows")
    finally:
        await close_db()
        mongo_client.close()


if __name__ == "__main__":
    asyncio.run(migrate())